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Biomedical subjects

P M Fernhoff

Publications and source records attributed to P M Fernhoff.

At least 37 records · Page 2Linked to original sources

Prenatal diagnosis of 21-hydroxylase deficiency by the complementary deoxyribonucleic acid probe for cytochrome P-450C-21OH.

The availability of the complementary deoxyribonucleic acid probe for cytochrome P-450C-21OH and the identification of specific gene defects in some families with congenital adrenal hyperplasia have made prenatal diagnosis feasible. Deoxyribonucleic acid samples from amniocytes of a fetus at 16 weeks' gestation, one previously affected son, and their parents were digested with the restriction enzymes Tag1 [corrected] or EcoRI and hybridized to the cytochrome P-450C-21OH complementary deoxyribonucleic acid probe. The previously affected son and the fetus both lacked the Tag1 [corrected] 3.7 kb band. At the time of delivery, the second child had a cord blood 17 alpha-hydroxyprogesterone level of 8000 ng/dl. The absence of the 3.7 kb Tag1 [corrected] fragment in affected members of this family made possible the use of deoxyribonucleic acid analysis for prenatal diagnosis.

17-alpha-Hydroxyprogesterone↗

Congenital hypothyroidism: increased risk of neonatal morbidity results in delayed treatment.

In a population-based screen of 617,913 infants, primary congenital hypothyroidism (CH) was confirmed in 100 children. 32 of the 100 infants with CH had an additional defect or complication. In the group with CH the rates of congenital heart disease, non-cardiac malformations, respiratory distress syndrome, and death were higher than in the general population of the same age. Black infants were less likely than whites to have CH, but were at twice the risk of additional impairment. Infants with CH who had an additional complication were screened (12.7 vs 4.8 days) and treated (32.4 vs 19.7 days) significantly later than those infants with isolated CH. Congenital malformations and neonatal complications should not be reasons for deferring screening for CH.

Congenital Abnormalities↗

Retinoic acid embryopathy.

Retinoic acid, an analogue of vitamin A, is known to be teratogenic in laboratory animals and has recently been implicated in a few clinical case reports. To study the human teratogenicity of this agent, we investigated 154 human pregnancies with fetal exposure to isotretinoin, a retinoid prescribed for severe recalcitrant cystic acne. The outcomes were 95 elective abortions, 26 infants without major malformations, 12 spontaneous abortions, and 21 malformed infants. A subset of 36 of the 154 pregnancies was observed prospectively. The outcomes in this cohort were 8 spontaneous abortions, 23 normal infants, and 5 malformed infants. Exposure to isotretinoin was associated with an unusually high relative risk for a group of selected major malformations (relative risk = 25.6; 95 per cent confidence interval, 11.4 to 57.5). Among the 21 malformed infants we found a characteristic pattern of malformation involving craniofacial, cardiac, thymic, and central nervous system structures. The malformations included microtia/anotia (15 infants), micrognathia (6), cleft palate (3), conotruncal heart defects and aortic-arch abnormalities (8), thymic defects (7), retinal or optic-nerve abnormalities (4), and central nervous system malformations (18). The pattern of malformation closely resembled that produced in animal studies of retinoid teratogenesis. It is possible that a major mechanism of isotretinoin teratogenesis is a deleterious effect on cephalic neural-crest cell activity that results in the observed craniofacial, cardiac, and thymic malformations.

Abnormalities, Drug-Induced↗

Thiamine response in maple syrup urine disease.

We measured the biochemical response for four patients with maple syrup disease to pharmacologic doses of thiamine, and correlated their response to their branched chain alpha-ketoacid dehydrogenase activity. We observed a linear correlation between the concentrations of each plasma branched-chain amino acid and its corresponding ketoacid analogue. In addition, the renal tubular reabsorption of branched-chain amino and ketoacids was nearly complete within these physiologic concentrations. Three children responded to thiamine therapy with a reduction in concentration of plasma and urinary branched-chain amino and ketoacids. Each responder had at least 5% activity for branched chain alpha-ketoacid dehydrogenase in their mononuclear blood cells and in whole cell fibroblasts from cultured skin when compared to the activity in normal control cells. We propose that each child with maple syrup urine disease be assessed for their response to thiamine by quantifying the concentration of branched-chain amino acids in plasma before and after vitamin supplementation.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗

Neonatal ethanol withdrawal: characteristics in clinically normal, nondysmorphic neonates.

Although neonatal withdrawal syndrome is often noted in infants of narcotics addicts, ethanol withdrawal has been reported only among neonates with fetal alcohol syndrome. To examine the possibility that ethanol withdrawal occurs more widely and to identify its characteristics, the behavior of eight neonates born to women who drank a mean of 21 ounces of absolute alcohol per week during gestation was compared with that of two contrast groups: 15 infants whose mothers drank an equivalent amount but stopped in the second trimester, and 29 infants whose mothers never drank. None of the 52 infants had fetal alcohol syndrome, and all were in good health. Neurobehavioral evaluation 3 days postnatally compared the groups for the occurrence of characteristic signs of withdrawal from central nervous system depressants. Whereas there was no difference in the frequency of withdrawal symptoms among infants of mothers who never drank (mean 1.4) or of mothers who stopped drinking (mean 1.8), infants of mothers who continued to drink (mean 4.7) had significantly more tremors, hypertonia, restlessness, excessive mouthing movements, unconsolable crying, and reflex abnormalities. By interfering with state control and interactive behaviors, withdrawal could affect mother-infant bonding as well as the conditions that foster cognitive and social development.

Alcohol Drinking↗

Zinc status and growth of children undergoing treatment for phenylketonuria.

Children with phenylketonuria (PKU) are treated with semi-synthetic diets restricted in phenylalanine. Low-phenylalanine or phenylalanine-free formulae provide the majority of protein and energy in the diet while phenylalanine requirements are met by low-protein natural foods. Because of the restriction of natural protein sources in this diet, the study assessed the zinc nutrition of 22 treated children with PKU (aged from 1 month to 8 1/2 years) and correlated linear growth with zinc status. The mean (+/- SE) plasma zinc concentration of the PKU population was 66.6 +/- 3.3 micrograms/dl. The mean (+/- SE) hair zinc concentration was 70.2 +/- 11.5 micrograms/g. The mean plasma and hair zinc concentrations of the PKU population were significantly different (p less than 0.05) when compared with mean (+/- SE) normal values of 84.2 +/- 2.9 micrograms/dl and 130.7 +/- 8.3 micrograms/g, respectively. The mean (+/- SD) dietary zinc intake of 10 PKU patients was 8.56 +/- 2.68 mg/day. No significant differences (p less than 0.123) were found when the mean zinc intake was compared with National Academy of Sciences Recommended Dietary Allowance for age of 10 mg/day. No significant correlations were found when plasma and hair zinc concentrations were plotted with height percentiles. Further studies are required to assess the effects of zinc supplementation and the bioavailability of zinc from low-phenylalanine diets.

Child↗

The effects of spacing protein intake on nitrogen balance and plasma amino acids in a child with propionic acidemia.

The effect of protein distribution on nitrogen balance and the plasma aminogram was studied in a 34-month-old male child with propionic acidemia. Protein provided 4.8% of energy of which high biological value protein was given either as a bolus or evenly distributed in three meals per day. Analysis of nitrogen balance including estimated sweat nitrogen losses revealed no major difference between the two diets. No marked differences in the fasting plasma concentrations of essential amino acids were noted with protein distribution. A generalized increase in concentration of all nonessential amino acids except taurine and ornithine was noted when protein was evenly distributed throughout the day. The ratio of nonessential to essential amino acids was higher after even protein distribution than when protein was given as a bolus. The data suggests that a low protein diet (206 mg nitrogen/kg/day) with adequate energy intake used in managing this child with propionic acidemia provided adequate amounts of total nitrogen and essential amino acids for normal growth regardless of protein distribution.

Amino Acid Metabolism, Inborn Errors↗

Coordinated system for comprehensive newborn metabolic screening.

In September 1978 phenylketonuria (PKU) screening in the state of Georgia was expanded to include testing for five additional metabolic disorders. Our goal was to begin therapy within the first three weeks of an infant's life. During the first 22 months, 167,458 specimens were received; 151,250 from infants less than or equal to 1 week of age. During this period 157,893 live births were reported. More than 90% of 2,299 infants with abnormal screening results were retested. The number of cases and incidence of each disease detected were hyperphenylalaninemia, five (1/31,579); maple syrup urine disease, 0 (0/151,250); homocystinuria, one (1/151,250); galactosemia, two (1/63,352); transient tyrosinemia (greater than or equal to 12 mg/dl), 50 (1/3,158); primary congenital hypothyroidism, 17 (1/7,453); and thyroid binding globulin deficiency, ten (1/12,670). For eight children with either hyperphenylalaninemia, homocystinuria, or galactosemia, the average time for retrieval between the initial abnormal screening result ad the first follow-up test was 6.2 days (range three to ten days). Therapy was started by 9.9 days of age (range seven to 17). For the 17 children with congenital hypothyroidism, the retrieval time was 11.6 days (range three to 27) and treatment began by 21.3 days of age (range ten to 69 days).

Academic Medical Centers↗

Epinephrine deficiency in hypocorticotropic hypopituitary children.

In rats, adrenal medullary synthesis of epinephrine is impaired by ACTH deficiency and is not improved by replacement doses of glucocorticoid. We have evaluated plasma epinephrine and norepinephrine concentrations in 43 children, 8-15 yr old. These children were divided into 5 groups, with 6-10 per group: normals; children with isolated GH deficiency; hypopituitary children deficient in both GH and TSH; hypopituitary children deficient in GH, TSH, and ACTH; and short children without known organic disease. The deficiencies of ACTH and TSH were being treated with replacement doses of cortisol and T4. Plasma catecholamines were measured in the supine position at rest every other hour from 0800-1600 h, and after exercise in the standing position at 1000 h. Plasma norepinephrine levels, both at rest and after exercise, were normal in all four groups of short children. Resting and postexercise plasma epinephrine levels were reduced to 10-20% of normal in the hypocorticotropic hypopituitary patients, and were normal in the other three groups of short children.

Adipose Tissue↗

Acceptance of amniocentesis by low-income patients in an urban hospital.

A study was made of increased accessibility of genetic services to low-income obstetric patients in Atlanta, Georgia. The proportion of black patients averaged 83%. Of 522 patients counseled from August, 1976, through 1978, 157 were offered amniocentesis, and 95 (61%) elected the procedure. For most of the patients (120, or 76%) who were eligible for amniocentesis, age (greater than or equal to 35 years at delivery) was an indication; and of these, only six (5%) had any prior knowledge of genetic risk. During the same time interval, 188 patients over 35 years of age who initiated prenatal care too late for prenatal diagnosis were counseled in the hospital after delivery; 101 (54%) indicated that they would have accepted amniocentesis. The conclusion was that (1) genetic services are acceptable to this socioeconomic group, and (2) accessibility and publicity are needed to promote utilization in this population.

Amniocentesis↗

Limitations of amniography in the prenatal diagnosis of spina bifida.

A fetus with an open, noncystic myelomeningocele was detected at the 22nd week of gestation in a woman monitored for advanced maternal age. The lesion could not be demonstrated on amniography. In 13% of published reports amniography failed to detect significant spina bifida lesions. This false-negative rate seems related to the noncystic nature of some neural tube defects at midgestation.

Amniotic Fluid↗

Prenatal diagnosis of a de novo non-fluorescent Y chromosome.

We report a case with non-mosaic Yq-, missing the fluorescent segment, and detected as a fetus studied for advanced maternal age. The father had a Y chromosome of average size and paternity was established wih a plausibility of 97.7% by HLA and erythrocyte antigen typing. The child had a normal male antigen typing. The child had a normal male phenotype at delivery and developmental milestones were normal through the first year of life. The Yq- showed no mitotic instability since it was retained in foreskin culture for its in vitro lifetime of 60 population doublings.

Adult↗